1. Field of the Invention
The invention relates to a method for converting heat into mechanical work, in which a working medium is compressed in a cyclic process while giving off heat and is subsequently brought in thermal contact with the ambient environment via a first heat exchanger, is then expanded while obtaining mechanical work, whereupon the cyclic process is run through again.
2. Description of the Related Art
Numerous working methods are known to convert thermal energy into mechanical work. Usually, a working medium is compressed, heated, expanded in the heated state and cooled in such cyclic processes, whereupon the cyclic process starts again. The precondition for such cyclic processes is that two different temperature levels are available which are used for heating or cooling the working medium. Generally, a certain temperature is defined as the ambient temperature, which is the temperature of a medium which is available in an unlimited and gratuitous way. This can be the air temperature of the ambient environment for example or the temperature of a water body from which water can be taken in sufficient quantities for purposes of temperature exchange.
No cyclic processes are known with which it is possible to gain mechanical work from thermal energy without disposing over a heat transfer medium whose temperature differs substantially from ambient temperature. According to current substantially from ambient temperature. According to current belief such a cyclic process is excluded by the second law of thermodynamics. It is stated in a more precise version of the second law of thermodynamics that the efficiency of any cyclic process for converting thermal energy into mechanical work cannot exceed the so-called Carnot efficiency which is calculated from the ratio of the available temperature levels. Real existing methods and apparatuses are generally also far away from the Carnot efficiency.
Apparatuses for generating temperature differences are known which use gas-dynamic effects occurring at high accelerations in order to produce temperature differences. These apparatuses are not suitable in order to perform cyclic processes for gaining mechanical work.
DE 38 12 928 A shows an apparatus which tries to overcome the above disadvantages. Even with such an apparatus it is not possible to improve the efficiency to a relevant extent.
It is the object of the present invention to provide a method of the kind mentioned above which allows obtaining mechanical work from thermal energy with the highest possible efficiency.
It is a further object of the invention to provide an apparatus with which the method in accordance with the invention can be performed.